An engine operates between temperature limits of 900K and T and T and 400K. For both to be equally efficient, the value of T will be
- A. 700 K
- B. 600 K
- C. 750 K
- D. 650 K
Answer: B. 600 K
Explanation: For equal efficiency, T is the geometric mean: T = \sqrt{T_H T_L} = \sqrt{900 * 400} = \sqrt{360000} = 600 K.